Abstract
The roller burnishing and deep rolling of drill holes or other profiles is a well established process for achieving a very high surface quality and for significantly enhancing the fatigue strength. With the development of the rolling-in process for manufacturing composite workpieces such as e. g. composite shafts and camshafts the possible fields of application of the rolling process can be extended by an interesting aspect. For rolling-in, specially adapted tools were used with a higher rolling oversize to join by expanding an inner component inside an outer part, both parts optimised to meet special requirements regarding their material and shape. Additionally it is much easier to manufacture the components before fixing them on the tube.
In the context of the presented investigations different correlations between the joining parameters and their effects on the torque stability of the joining connection are pointed out. Thereby the influence of the parameters such as revolution, feed rate, rolling length, surface roughness, wall thickness of the inner and outer component, rolling oversize and clearance was investigated. By choosing appropriate parameters, the joining connection of a specimen with an internal tube diameter of 20 mm was able to transmit torques of more than 200 Nm. The maximum torque for common automotive camshafts is usually less than approximately 50 Nm, for example. Additionally the rolling-in process can be described as a favourable and simple process, as it is not necessary to precisely tolerate the components. Moreover the potential of the process in manufacturing of lightweight composites of the power train is pointed out by an example of a composite camshaft. To enlarge the possible fields of applications of the rolling-in process, a new process named profile rolling-in is introduced. With this new process it is possible to transfer the experiences from the cylindrical rolling-in process to the joining of non-cylindrical component profiles.
Keywords: Rolling-in, Composite Camshafts or other Workpieces, Lightweight Construction Frames, Cylindrical Profiles, Non-Cylindrical Profiles